Heatwave alert: IMD warns of 45 degrees in north, central India over next 3 days
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Context
The has issued warnings for severe heatwave conditions across northwest, central, and parts of peninsular India, with temperatures expected to reach 45°C. The prolonged high temperatures, significantly above normal (3°C to 5°C deviation), highlight the increasing frequency and intensity of extreme weather events in the subcontinent during the pre-monsoon season.
UPSC Perspectives
Geographical
A heatwave is a period of abnormally high temperatures, more than the normal maximum temperature that occurs during the summer season. The declares a heatwave when the maximum temperature of a station reaches at least 40°C for Plains and at least 30°C for Hilly regions. Additionally, the departure from normal must be 4.5°C to 6.4°C for a 'heat wave', and greater than 6.4°C for a 'severe heat wave'. Alternatively, a heatwave is declared if the actual maximum temperature remains 45°C or more irrespective of normal maximum temperature. The current heatwave is driven by the absence of active Western Disturbances and prevailing anticyclonic conditions that cause subsidence of air (air sinking and warming). This prevents cloud formation and leads to intense solar heating. For UPSC Prelims, understanding the exact criteria for declaring heatwaves and the role of localized pressure systems is crucial.
Environmental
The increasing frequency, duration, and intensity of heatwaves in India are consistent with global climate change projections. Studies indicate that anthropogenic warming has significantly multiplied the probability of extreme heat events in South Asia. This relates directly to the broader issue of global warming and its localized impacts. The rising temperatures exacerbate the Urban Heat Island (UHI) effect in cities like Delhi and Mumbai, where concrete and asphalt absorb and retain heat, causing nighttime temperatures to remain uncomfortably high (e.g., Delhi's minimum near 35°C). This lack of nighttime cooling prevents the human body from recovering from daytime heat stress. For UPSC Mains (GS-3), this event serves as a critical example when discussing the impacts of climate change on the Indian subcontinent and the urgent need for climate adaptation strategies.
Governance
Managing heatwaves falls under the purview of Disaster Management. While the does not explicitly list heatwaves as a 'notified disaster' eligible for relief under the , it has issued comprehensive guidelines for state governments to prepare Heat Action Plans (HAPs). These plans typically include early warning systems (like the 's color-coded alerts), public awareness campaigns, adjusting working hours for outdoor laborers, and ensuring water availability. The issuance of a 'yellow alert' for Delhi signifies 'Watch' and stay updated. The governance challenge lies in effectively implementing these HAPs at the local level, particularly protecting vulnerable populations (the elderly, children, and outdoor workers) who face severe health risks like heatstroke and dehydration. UPSC questions often focus on evaluating the effectiveness of India's disaster management framework regarding slow-onset disasters like heatwaves.